Podcast
Questions and Answers
What is the first step in designing a system that supports millions of users?
What is the first step in designing a system that supports millions of users?
- Building a complex system from the beginning
- Purchasing a domain name and hosting DNS services on our servers
- Setting up a single server to run everything initially (correct)
- Configuring multiple servers to handle different tasks
Which component is typically not hosted by the system’s servers when users access websites through domain names?
Which component is typically not hosted by the system’s servers when users access websites through domain names?
- Domain Name System (DNS) (correct)
- HTML pages or JSON response
- Hypertext Transfer Protocol (HTTP)
- Internet Protocol (IP) address
What protocol are HTTP requests sent through to the web server?
What protocol are HTTP requests sent through to the web server?
- Domain Name System (DNS)
- Hypertext Transfer Protocol (HTTP) (correct)
- Internet Protocol (IP)
- Transmission Control Protocol (TCP)
What is the purpose of the single server setup illustrated in Figure 1?
What is the purpose of the single server setup illustrated in Figure 1?
What is the primary benefit of database replication for system performance?
What is the primary benefit of database replication for system performance?
In the event of a database failure, how can the system handle the situation?
In the event of a database failure, how can the system handle the situation?
What is the purpose of a cache in a system architecture?
What is the purpose of a cache in a system architecture?
What should be considered when deciding to use a cache in a system?
What should be considered when deciding to use a cache in a system?
How can cached data be prevented from becoming stale?
How can cached data be prevented from becoming stale?
What is the purpose of keeping the data store and the cache in sync?
What is the purpose of keeping the data store and the cache in sync?
Why is it advisable to use multiple cache servers across different data centers?
Why is it advisable to use multiple cache servers across different data centers?
What is the purpose of overprovisioning cache servers?
What is the purpose of overprovisioning cache servers?
What is the purpose of a content delivery network (CDN)?
What is the purpose of a content delivery network (CDN)?
Which caching policies are commonly used in cache eviction?
Which caching policies are commonly used in cache eviction?
What does a stateful server do compared to a stateless server?
What does a stateful server do compared to a stateless server?
Why is setting an appropriate cache expiry time important in a CDN?
Why is setting an appropriate cache expiry time important in a CDN?
What is the purpose of moving state data out of the web tier in a stateless web tier architecture?
What is the purpose of moving state data out of the web tier in a stateless web tier architecture?
How does a CDN workflow function when a user visits a website?
How does a CDN workflow function when a user visits a website?
What is the benefit of fetching static assets from a CDN instead of web servers?
What is the benefit of fetching static assets from a CDN instead of web servers?
What is the primary function of a load balancer in a web server environment?
What is the primary function of a load balancer in a web server environment?
What type of databases are suitable for low latency, unstructured data, and large data sets?
What type of databases are suitable for low latency, unstructured data, and large data sets?
Which method is better for handling high traffic in large scale applications?
Which method is better for handling high traffic in large scale applications?
What is the primary benefit of separating web/mobile traffic and database servers?
What is the primary benefit of separating web/mobile traffic and database servers?
In a master/slave relationship, what is the role of slave databases in database replication?
In a master/slave relationship, what is the role of slave databases in database replication?
Which feature makes non-relational databases suitable for serialization/deserialization requirements?
Which feature makes non-relational databases suitable for serialization/deserialization requirements?
What is the main advantage of using vertical scaling for low traffic scenarios?
What is the main advantage of using vertical scaling for low traffic scenarios?
What communication protocol does the mobile application use to interact with the web server?
What communication protocol does the mobile application use to interact with the web server?
Which type of databases are suitable for join operations using SQL?
Which type of databases are suitable for join operations using SQL?
What is the main purpose of using database replication in a system?
What is the main purpose of using database replication in a system?
What is the primary function of a relational database?
What is the primary function of a relational database?
What is the key benefit of using non-relational databases for large data sets?
What is the key benefit of using non-relational databases for large data sets?
What is the primary purpose of GeoDNS in a multi-data center setup?
What is the primary purpose of GeoDNS in a multi-data center setup?
What is the purpose of message queues in a system with independent scaling?
What is the purpose of message queues in a system with independent scaling?
What is the primary benefit of database replication for system performance?
What is the primary benefit of database replication for system performance?
What is the purpose of horizontal database scaling?
What is the purpose of horizontal database scaling?
What protocol are HTTP requests sent through to the web server?
What protocol are HTTP requests sent through to the web server?
What is the purpose of a cache in a system architecture?
What is the purpose of a cache in a system architecture?
Why is it advisable to use multiple cache servers across different data centers?
Why is it advisable to use multiple cache servers across different data centers?
In the event of a database failure, how can the system handle the situation?
In the event of a database failure, how can the system handle the situation?
What should be considered when deciding to use a cache in a system?
What should be considered when deciding to use a cache in a system?
What is the purpose of overprovisioning cache servers?
What is the purpose of overprovisioning cache servers?
What is the first step in designing a system that supports millions of users?
What is the first step in designing a system that supports millions of users?
Study Notes
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Database replication improves system performance by allowing read operations to be processed in parallel across multiple servers (slave nodes), while writes and updates are processed in master nodes.
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Replication improves system reliability by preserving data across multiple locations, preventing data loss in the event of a natural disaster or server failure.
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In case of a database failure, the system can handle the situation by redirecting read operations to available slave databases or promoting a healthy slave database to be the new master.
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A cache is a temporary storage area that stores the result of expensive responses or frequently accessed data in memory for faster access, reducing the load on the database and improving system performance.
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Cache servers provide APIs for common programming languages, making it simple to interact with them.
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Decide when to use a cache based on data access patterns: use it when data is read frequently but modified infrequently, and save important data in persistent data stores.
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Implement an expiration policy for cached data to prevent it from being stored in volatile memory indefinitely and becoming stale.
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Keep the data store and the cache in sync to avoid inconsistencies.
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Use multiple cache servers across different data centers to avoid a single point of failure and maintain system availability.
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Overprovision cache servers by certain percentages to handle increased traffic and ensure sufficient memory is available.
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After removing state data from web servers, auto-scaling of web tier is achieved by adding or removing servers based on traffic load.
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Geo-routed traffic to closest data center using GeoDNS in normal operation, split traffic between data centers.
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In the event of a data center outage, all traffic is directed to a healthy data center.
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Multi-data center setup requires solving challenges like traffic redirection (using GeoDNS) and data synchronization (replicating data across multiple data centers).
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Decoupling different components of the system through message queues for independent scaling.
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Message queues serve as a buffer distributing asynchronous requests with producers and consumers interacting asynchronously.
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Logging, monitoring, metrics, and automation are essential for large-scale websites for error identification, business insights, and system health.
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Database scaling approaches include vertical scaling (adding more power to existing machine) and horizontal scaling (adding more machines).
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Vertical scaling can store and handle large amounts of data using powerful database servers.
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Database servers can be extremely powerful, Amazon RDS offers a server with 24 TB of RAM.
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stackoverflow.com in 2013 had over 10 million monthly users, demonstrating the scale that can be achieved with powerful database servers.
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Description
Learn about the advantages of database replication, such as improved performance and increased reliability. Explore how the master-slave model distributes read and write operations, enhancing parallel query processing and preserving data in case of server destruction.
